A generalized ellipsometer with wide spectrum and double variable incident angle system

Abstract

The present invention belongs to the technical field of generalized ellipsometers, and specifically relates to a generalized ellipsometer with a wide spectrum double variable incident angle system, including a high-band measurement system, a sample and a low-band measurement system, wherein the low-band measurement system includes a polarizing arm 1 and an analyzing arm 1, wherein the sample is arranged in the optical path direction of the polarizing arm 1, and the analyzing arm 1 is arranged in the transmission optical path direction of the sample, and the high-band measurement system includes a polarizing arm 2 and an analyzing arm 2, wherein the sample is arranged in the optical path direction of the polarizing arm 2, and the analyzing arm 2 is arranged in the reflection optical path direction of the sample. The present invention uses two systems to complete the measurement of the entire wide spectrum range at a single time, and only needs to reasonably decompose the entire wide spectrum band so that each decomposed spectrum band can be measured in a separate system. The spectrum range that can be measured at a single time by the generalized ellipsometer designed by the structure of the present invention can be wider than the spectrum range that can be measured at a single time by the existing generalized ellipsometer.

Description

Technical Field

[0001] The invention belongs to the technical field of generalized ellipsometers, and in particular relates to a generalized ellipsometer with a wide spectrum and double variable incident angle system. Background Art

[0002] Ellipsometry is a multifunctional optical measurement technology that measures the change in polarization state of the object before and after polarized light is incident on it to obtain its optical constants (refractive index n, extinction coefficient k), surface morphology, thickness and other parameters.

[0003] Ellipsometer (ellipsometer for short) is an optical instrument that uses the polarization characteristics of light to measure the interface parameters of thin films or nanostructures. Its basic principle is to project special elliptically polarized light onto the surface of the sample to be tested through a polarizer, and measure the reflected light (or transmitted light) of the sample to be tested to obtain the polarization state change (including amplitude ratio and phase difference) of the polarized light before and after reflection (or transmission) and then extract the information of the sample to be tested. Although the traditional spectroscopic ellipsometer has shown good performance in the measurement of thin film materials and even micro-nano structures, its principle only considers the situation that the p component and the s component do not interact after the detection light is reflected by the surface of the isotropic material, but does not consider the situation that the p component and the s component will transform into each other after the detection light is reflected by the surface of the anisotropic material, that is, the amplitude ratio and phase difference are obtained by changing only the two measurement conditions of wavelength and incident angle. Therefore, the data obtained from the detection of anisotropic materials is neither comprehensive nor accurate, so the generalized ellipsometer is introduced.

[0004] Generalized ellipsometer is a non-contact, non-destructive and high-precision thin film measurement technology. Generalized ellipsometer (also known as full Mueller matrix ellipsometer) is developed by combining traditional ellipsometer with generalized ellipsometer technology. It can obtain all 16 elements of the Mueller matrix in a single measurement, thereby providing more useful information to be measured, such as anisotropy, micro-nanostructure surface morphology and depolarization, etc., so it can obtain richer measurement information than traditional spectroscopic ellipsometer. The generalized ellipsometer based on dual rotating compensators can obtain all 16 normalized Mueller matrix elements of the sample to be measured in one measurement, and there is no need to reconfigure the measurement system. Therefore, the measurement speed will be much faster, and it is also suitable for applications with higher requirements such as real-time measurement.

[0005] Nowadays, both at home and abroad, great attention has been paid to the research of generalized ellipsometers. Domestic ellipsometer manufacturers include Beijing Liangtuo Technology, Wuhan Yiguang Technology, etc., but there is still a big gap compared with the most representative generalized ellipsometer manufacturer abroad, JA Woolam of the United States. Among them, Wuhan Yiguang Technology's ME-L fully automatic high-precision Mueller matrix ellipsometer has a maximum measurable range of 193-2500nm, and the maximum measurable range of JA Woolam of the United States is 193-3200nm, but the existing wide spectral range generalized ellipsometers at home and abroad have extremely narrow choices in optical devices, and some even need to be specially customized, resulting in the high cost of their ellipsometers, and the measurable spectral range is still very limited. Summary of the invention

[0006] In view of the technical problem that the measurable spectral range of the existing generalized ellipsometer with a wide spectral range is still very limited, the present invention provides a generalized ellipsometer with a wide spectrum and a dual-variable incident angle system. Through the dual-variable incident angle structure, the original unmeasurable complete spectral range is divided into two parts, wherein accurate data of each part of the spectral range can be measured based on existing optical components, thereby achieving the purpose of greatly expanding the measurable spectral range of the existing generalized ellipsometer, reducing its manufacturing cost and improving the measurement accuracy.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A generalized ellipsometer with a wide spectrum and a double variable incident angle system comprises a high-band measurement system, a sample and a low-band measurement system. The low-band measurement system comprises a first polarizing arm and a first analyzing arm, the sample is arranged in the optical path direction of the first polarizing arm, and the first analyzing arm is arranged in the transmission optical path direction of the sample. The high-band measurement system comprises a second polarizing arm and a second analyzing arm, the sample is arranged in the optical path direction of the second polarizing arm, and the second analyzing arm is arranged in the reflection optical path direction of the sample.

[0009] The polarizing arm 1 includes a light source 1, a collimation system 1, a polarizer 1, a first servo motor, and a first compensator. The collimation system 1, the polarizer 1, and the first compensator are arranged in sequence in the light path direction of the light source 1. A sample is arranged in the light path direction of the first compensator, and the bottom of the first compensator is connected to the first servo motor.

[0010] The analyzer arm 1 includes a second compensator, a second servo motor, an analyzer 1, a beam splitter, a collimation system 2, a spectrometer 1, a collimation system 3, and a spectrometer 2. The second compensator is arranged in the direction of the transmission light path of the sample. The light path direction of the second compensator is sequentially arranged with the analyzer 1 and the beam splitter. The transmission light path of the beam splitter is arranged with the collimation system 2. The light path direction of the collimation system 2 is arranged with the spectrometer 1. The reflected light path of the beam splitter is arranged with the collimation system 3. The spectrometer 2 is arranged in the light path direction of the collimation system 3. The bottom of the second compensator is connected to a second servo motor.

[0011] The polarizing arm 2 includes a light source 2, a collimation system 4, a polarizer 2, a third servo motor, and a third compensator. The collimation system 4, the polarizer 2, and the third compensator are sequentially arranged in the light path direction of the light source 2. A sample is arranged in the light path direction of the third compensator, and the bottom of the third compensator is connected to a third servo motor.

[0012] The second analyzer arm includes a fourth compensator, a fourth servo motor, a second analyzer, a fifth collimation system, and a third spectrometer. The fourth compensator is arranged in the direction of the reflected light path of the sample. The second analyzer, the fifth collimation system, and the third spectrometer are arranged in sequence in the light path direction of the fourth compensator. The bottom of the fourth compensator is connected to a fourth servo motor.

[0013] The polarizing arm 1 and the polarizing arm 2 are fixed on the same base plate, the incident angle range of the polarizing arm 1 and the polarizing arm 2 is 15°-90°, the ratio of the sample rotation angle to the rotation angle of the polarizing arm 1 is 1:2, and the ratio of the sample rotation angle to the rotation angle of the polarizing arm 2 is 1:2.

[0014] The light source 1 adopts a DH-200-DUV light source, and the spectral range of the DH-200-DUV light source is 190-2500nm. The light source 2 adopts an Arclight NIR&IR lamps light source, and the spectral range of the Arclight NIR&IR lamps light source is 400-4000nm.

[0015] The transmission band range of the beam splitter is 190-1000nm, the reflection band range of the beam splitter is 1000nm-2500nm, the first compensator and the second compensator adopt JGS1 material FRR-F102 type single rhombus Fresnel prism phase retarder, and the third compensator and the fourth compensator adopt ZnSe material FRR-S104 type double rhombus Fresnel prism phase retarder.

[0016] The first polarizer and the second polarizer both adopt Rochon prism polarizers made of a-BBO material, and the applicable wavelength range of the Rochon prism polarizers made of a-BBO material is 190nm-3500nm.

[0017] The spectrometer 1 adopts a maya2000pro spectrometer, and the measurable range of the maya2000pro spectrometer is 165-1100nm; the spectrometer 2 adopts a NIRQuest512+2.5 spectrometer, and the measurable range of the NIRQuest512+2.5 spectrometer is 900-2500nm; the spectrometer 3 adopts an ARCoptix FT-IR Rocket spectrometer, and the measurable range of the ARCoptix FT-IR Rocket spectrometer is 2000-6000nm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention uses two systems to complete the measurement of the entire wide spectral range at a time. It only needs to reasonably decompose the entire wide spectrum so that each decomposed spectrum can be measured in a separate system. Compared with the existing generalized ellipsometer, the advantages of the present invention are: 1. The spectral range that can be measured at a time by the generalized ellipsometer designed by the structure of the present invention can be wider than the spectral range that can be measured at a time by the existing generalized ellipsometer; 2. The present invention has low requirements for the corresponding optical devices, that is, it only needs to complete the corresponding measurement within the corresponding narrow band. There are many such optical components on the market, and the price is relatively low; 3. The present invention can more easily take into account a wider spectral range and higher measurement accuracy. The generalized ellipsometer designed by using such a structure can have better accuracy and range in a single measurement than the existing generalized ellipsometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0021] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 It is a structural schematic diagram of the deflecting arm 1 of the present invention;

[0024] Figure 3 It is a schematic structural diagram of the first analyzing arm of the present invention;

[0025] Figure 4 It is a structural schematic diagram of the second deflecting arm of the present invention;

[0026] Figure 5 This is a schematic structural diagram of the second detection arm of the present invention;

[0027] Figure 6 It is a schematic diagram of the motion range of the rotating arm of the present invention.

[0028] Among them: 1 is polarizing arm one, 2 is analyzing arm one, 3 is polarizing arm two, 4 is analyzing arm two, 5 is sample, 101 is light source one, 102 is collimating system one, 103 is polarizer one, 104 is first servo motor, 105 is first compensator, 201 is second compensator, 202 is second servo motor, 203 is analyzer one, 204 is beam splitter, 205 is collimating system two, 206 is spectrometer one, 207 is collimating system three, 208 is spectrometer two, 301 is light source two, 302 is collimating system four, 303 is polarizer two, 304 is third servo motor, 305 is third compensator, 401 is fourth compensator, 402 is fourth servo motor, 403 is analyzer two, 404 is collimating system five, 405 is spectrometer three. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. These descriptions are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0032] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] The specific parameters in this embodiment are as follows:

[0034] Light source 101 uses DH-200-DUV light source, and the spectrum range of DH-200-DUV light source is 190-2500nm. Light source 2 301 uses Arclight NIR&IR lamps light source, and the spectrum range of Arclight NIR&IR lamps light source is 400-4000nm.

[0035] The transmission band of the beam splitter 204 is in the range of 190-1000 nm, and the reflection band of the beam splitter 204 is in the range of 1000 nm-2500 nm.

[0036] The first compensator 105 and the second compensator 201 use single rhombus Fresnel prism phase retarders of JGS1 material FRR-F102. The third compensator 305 and the fourth compensator 401 use double rhombus Fresnel prism phase retarders of ZnSe material FRR-S104.

[0037] The first polarizer 103 and the second polarizer 303 both use Rochon prism polarizers made of a-BBO material. The Rochon prism polarizers made of a-BBO material are applicable to a wavelength range of 190nm-3500nm.

[0038] Spectrometer 1 206 adopts maya2000pro spectrometer, and the measurable range of maya2000pro spectrometer is 165-1100nm; spectrometer 208 adopts NIRQuest512+2.5 spectrometer, and the measurable range of NIRQuest512+2.5 spectrometer is 900-2500nm; spectrometer 3 405 adopts ARCoptix FT-IR Rocket spectrometer, and the measurable range of ARCoptix FT-IR Rocket spectrometer is 2000-6000nm.

[0039] like Figure 1-5As shown, in the low-band measurement system composed of a polarizing arm 1 and an analyzing arm 2, a wide-spectrum composite light beam of 190-2500nm emitted by a light source 101 is collimated by a collimating system 102 and then enters a detection optical path; the light beam entering the detection optical path is polarized by a polarizer 103 and then passes through a first compensator 105 driven to rotate by a first servo motor 104; the light beam directly passes through the air or is reflected by the surface of a sample 5 on the platform to be measured, enters a second compensator 201 driven to rotate by a second servo motor 202, and is then analyzed by an analyzer 203 in turn, and a beam splitter 204 divides the complete band into two parts, 190-1000nm and 1000nm-2500nm, and then is introduced into a spectrometer 1 206 and a spectrometer 2 208 respectively through a collimating system 2 205 and a collimating system 3 207, to complete the measurement of the first band range. In this example, the spectrum range of the compensator is limited to 200nm-2100nm, so the measurable range of the low-band measurement system is 200nm-2100nm. In the high-band measurement system composed of the second polarizing arm 3 and the second analyzing arm 4, the wide spectrum composite light beam of 400nm-4000nm emitted by the second light source 301 is collimated by the fourth collimator system 302 and enters the detection light path; the light beam entering the detection light path is polarized by the second polarizer 303, and then passes through the third compensator 305 driven to rotate by the third servo motor 304; the light beam directly passes through the air or is reflected by the surface of the platform sample 5, enters the fourth compensator 401 driven to rotate by the fourth servo motor 402, and then is analyzed by the second analyzer 403 in turn, and then introduced into the spectrometer three 405 through the collimator system five 404, and the measurement of the high-band spectrum range is completed in the second analyzing arm 4. Although here, the measurable range of the spectrometer and the wavelength range of the light beam emitted by the light source are very wide, 2000nm-6000nm and 400nm-4000nm respectively, they are limited by the selected polarizer, that is, the Rochon prism polarizer of a-BBO material, which has an applicable wavelength range of 190nm-3500nm. Therefore, the theoretical measurable wavelength range of the high-band measurement system is 2000nm-3500nm, but considering that the wavelength range of 2000nm-2100nm can be measured in the low-band measurement system, only the spectrum within the wavelength range of 2100nm-3500nm is set in the high-band measurement system to complete the measurement.

[0040] It can be seen here that if a suitable polarizer is replaced in the high-band measurement system, the spectral measurable range of the ellipsometer can be easily expanded again. Furthermore, if a light source with a wider spectral range is replaced, the spectral range can be further extended to a higher spectral band. Similarly, replacing the corresponding optical components in the low-band measurement system can also extend the spectral range of the ellipsometer to the deep ultraviolet band.

[0041] The change of the incident angle is achieved by rotating the analyzer arm and the sample stage. Figure 6 To explain, Figure 6 Schematic diagram of the range of motion of the rotating arm. Due to the limitation of the relevant mechanical mechanism, this example takes the relevant mechanical structure as an example, but the present invention is not limited to the following. Figure 6 As shown, the polarizing arm 1 and the polarizing arm 2 3 are fixed respectively on Figure 6 In the position shown, the analyzer arm 2 of the low-band measurement system and the analyzer arm 2 4 of the high-band measurement system are fixed on the same base plate and move together with the angle changing mechanism to achieve the purpose of changing the incident angle. Since the maximum angle between the polarizing arm 1, the polarizing arm 2 3 and the analyzer arm 1 2, the analyzer arm 2 4 is 180 degrees, the minimum angle is 30 degrees, and the ratio of the rotation angle of the sample 5 to the rotation angle of the analyzer arm 2, the analyzer arm 2 4 is 1:2, the change of the incident angle in the range of 15 degrees to 90 degrees is achieved.

[0042] In summary, by taking the relevant optical components that can be used in the present invention as an example, the detection of 200nm-3500nm is completed, and the specific implementation process of the structure of the present patent is explained. Obviously, the corresponding optical devices provided in the examples of the present invention are not optimal in selection. Those skilled in the art can use better device selection based on the content disclosed in the present invention. Any design that adopts the design structure and ideas of the present invention and makes some simple changes or modifications falls within the scope of protection of the present invention.

[0043] Only the preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the protection scope of the present invention.

Claims

1. A generalized ellipsometer with a wide spectrum and dual variable incident angle system, characterized in that: The invention comprises a high-band measurement system, a sample (5) and a low-band measurement system, wherein the low-band measurement system comprises a polarizing arm (1) and an analyzing arm (2), wherein the sample (5) is arranged in the light path direction of the polarizing arm (1), and the analyzing arm (2) is arranged in the transmission light path direction of the sample (5); the high-band measurement system comprises a polarizing arm (3) and an analyzing arm (4), wherein the sample (5) is arranged in the light path direction of the polarizing arm (3), and the analyzing arm (4) is arranged in the reflection light path direction of the sample (5); the polarizing arm (1) comprises a light source (101), a collimating system (102), a polarizing arm (103), and a polarizing arm (104). The first polarizer arm (201) comprises a first polarizer (103), a first servo motor (104), and a first compensator (105); a collimation system (102), a polarizer (103), and a first compensator (105) are sequentially arranged in the direction of the optical path of the first light source (101); a sample (5) is arranged in the direction of the optical path of the first compensator (105); and the bottom of the first compensator (105) is connected to the first servo motor (104); the first polarizer arm (201) comprises a second compensator (201), a second servo motor (202), a polarizer (203), a beam splitter (204), a collimation system (205), a spectrometer (201), and a second polarizer (103). 06), collimation system three (207), spectrometer two (208), the second compensator (201) is arranged in the direction of the transmission light path of the sample (5), the light path direction of the second compensator (201) is sequentially arranged with a polarizer one (203), and a beam splitter (204), the transmission light path of the beam splitter (204) is provided with a collimation system two (205), the light path direction of the collimation system two (205) is provided with a spectrometer one (206), the reflection light path of the beam splitter (204) is provided with a collimation system three (207), and the light path direction of the collimation system three (207) is provided with a spectrometer Second (208), the bottom of the second compensator (201) is connected to a second servo motor (202); the second polarizing arm (3) comprises a second light source (301), a fourth collimation system (302), a second polarizer (303), a third servo motor (304), and a third compensator (305); the collimation system (302), the second polarizer (303), and the third compensator (305) are sequentially arranged in the direction of the light path of the second light source (301); a sample (5) is arranged in the direction of the light path of the third compensator (305); and the bottom of the third compensator (305) is connected to a third servo motor (304);The polarizer arm 2 (4) comprises a fourth compensator (401), a fourth servo motor (402), a polarizer 2 (403), a collimation system 5 (404), and a spectrometer 3 (405). The fourth compensator (401) is arranged in the direction of the reflected light path of the sample (5). The polarizer 2 (403), the collimation system 5 (404), and the spectrometer 3 (405) are arranged in sequence in the light path direction of the fourth compensator (401). The bottom of the fourth compensator (401) is connected to the fourth servo motor (402). The polarizer arm 1 (2) and the polarizer arm 2 (4) are fixed on the same bottom plate. The incident angle range of the polarizer arm 1 (1) and the polarizer arm 2 (3) is 15°-90°. The ratio of the rotation angle of the sample (5) to the rotation angle of the polarizer arm 1 (2) is 1:

2. The ratio of the rotation angle of the sample (5) to the rotation angle of the polarizer arm 2 (4) is 1:

2.

2. The generalized ellipsometer with a wide spectrum and dual variable incident angle system according to claim 1, characterized in that: The light source one (101) adopts a DH-200-DUV light source, and the spectral range of the DH-200-DUV light source is 190-2500nm. The light source two (301) adopts an Arclight NIR&IR lamps light source, and the spectral range of the Arclight NIR&IRlamps light source is 400-4000nm.

3. The generalized ellipsometer with a wide spectrum and dual variable incident angle system according to claim 1, characterized in that: The transmission band range of the beam splitter (204) is 190-1000nm, the reflection band range of the beam splitter (204) is 1000nm-2500nm, the first compensator (105) and the second compensator (201) use JGS1 material FRR-F102 type single rhombus Fresnel prism phase retarders, and the third compensator (305) and the fourth compensator (401) use ZnSe material FRR-S104 type double rhombus Fresnel prism phase retarders.

4. The generalized ellipsometer with a wide spectrum and dual variable incident angle system according to claim 1, characterized in that: The first polarizer (103) and the second polarizer (303) are both Rochon prism polarizers made of a-BBO material. The applicable wavelength range of the Rochon prism polarizers made of a-BBO material is 190nm-3500nm.

5. The generalized ellipsometer with a wide spectrum and dual variable incident angle system according to claim 1, characterized in that: The spectrometer one (206) adopts a maya2000 pro spectrometer, and the measurable range of the maya2000 pro spectrometer is 165-1100nm; the spectrometer two (208) adopts a NIRQuest512+2.5 spectrometer, and the measurable range of the NIRQuest512+2.5 spectrometer is 900-2500nm; the spectrometer three (405) adopts an ARCoptix FT-IR Rocket spectrometer, and the measurable range of the ARCoptix FT-IR Rocket spectrometer is 2000-6000nm.

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